Pulsating pressure sensing device



June 14, 1966 w. E. woRLEY ETAL 3,255,633

PULSATING PRESSURE SENSING DEVICEV Filed June 27, 1965 40 3g/gil? Dieze-45W INVENTOR` w/u/M/ E. WOBLEY Peg/yc@ A. HEM/z Je.

A T TUE/VE' Y 3,255,633 PULSATING PRESSURE SENSING DEVICE William E. Worley and Francis A. Heinz, Jr., Mishawaka, Ind., assgnors to The Bendix Corporation, vMishawaka, Ind., a corporation of Delaware Filed June 27, 1963, Ser. No. 291,106 4 Claims. (Cl. 73-406) This invention relates to a pressure sensing device and more particularly to a device which is sensitive to pulsating or oscilla-ting pneumatic pressures.

It is an object `of this invention to provide a device which will detect pulsating or oscillating pneumatic pressures land will develop a force and/or displacement on an output shaft when subjected to such pressures.

Another object of this invention is to provide a device for detecting pulsating pressures which is not affected by steady state pressure applications.

A further object of this invention is to provide a device which could be used as 'an indicator Ifor detecting pulsating pressures or as a corrective device for 'activating a mechanism to stop pressure pulsations. For example, such a device could be used to reduce fuel ow to a ramjet engine when diffuser pressure pulsations occur because of ,an expelled normal shock wave. v

More particularly, it is an object of this invention to provide va device for detecting pulsating pressures which utilizes a diaphragm, both sides of which communicate with a pressure source, and two valves, one of which opens and permits unrestricted communication between the pressure source and one side of the diaphragm during the high pressure portion of a pulsating pressure cycle and the other of which opens `and permits unrestricted communication between the pressure source and the other side of the diaphragm during the low pressure portion of a pulsating pressure cycle to thereby create a differential pressure across said diaphragm and consequent movement of the diaphragm, said movement being utilized to indicate the existence of pulsating pressures or to activate a mechanism to stop unwanted pressure pulsations.

The above and other objects and features of the invention will become apparent from the following description of the device taken in connection with the accompanying drawing which forms a part of this specification and in which:

FIGURE 1 is a sectional schematic view of the pressure sensing device; and

FIGURE 2 is a graph showing a typical pulsating pneumatic pressure.

Referring to the drawing, it will be seen that the device comprises a housing 12 having a chamber therein which is divided int-o subchambers 14 and 16 by a diaphragm 18. Attached to the diaphragm is a control rod 20 which may be suitably connected to an indicator (not shown) :or to any mechanism (not shown) which is desired to be actuated upon the occurrence of pulsating pressures.

A pneumatic pressure source 22 communicates with subohambers 14 and 16 via passages 24 and 26, respectively. Located in passage 24 is a check valve 28 having a restrictive orifice 30 extending ltherethrough. A spring 32 urges the check valve to a normally closed position. However, in the drawing the valve 28 is shown in an open position after having moved away from valve seat 34. Another check valve 36, which is similar to check valve 28, is located in passage 26. This check valve a-lso has a restrictive orifice 38 extending therethrough and is urged against valve seat 40 by a spring 42.

Operation of the device will be as follows: When a pulsating 'pneumatic pressure emanates from uid pressure source 22, check valve 28 will be caused to open (as shown in FIGURE l) and check valve 36 will remain United States Patent O 3,255,633 Patented June 14, 1966 closed (as shown in FIGURE l) during the increasing or high pressure portion of the pulsating pressure cycle shown in FIGURE 2. With check valve 28 being unseated and permitting unrestricted communication between the lluid pressure source and subchamber 14 during the high pressure portion o-f the pulsating pressure cycle, the pressure in subchamber 14 will rise to a value which is higher than the mean pressure of the pulsating pressure cycle. Conversely, during the decreasing or low pres-sure portion of -the pulsating pressure cycle shown in FIGURE 2, check valve 28 will be caused to move away fromvalve seat 40 because of the differential pressure acting thereacross, and check valve 28 Will be in a seated or closed position. With check valve 36 -in an open position which will penmit unrestricted communication between the lluid pressure source and subchamber 16 during the low pressure portion of the pulsating pressure cycle, the pressure in subchamber 16 will decrease to a value which is lower than the mean pressure :of the pulsating pressure cycle.

Thus, upon the occurrence of a pulsating pressure cycle, the pressure in subchamber 14 will be higher than the mean pressure and the pressure in subchamber 16 will be lower than the mean pressure. As a result the differential pressure occurring across diaphragm 18 will cause movement of the diaphragm 18 and the control rod 20 in the direction shown on the drawing. As previously state, this movement of the rod 20 can be utilized to indicate the existence of pulsating pressures or to actuate a mechanism which will stop the pulsating pressures or compensate for the existence of such pressures.

It will be noted that the restrictive orifices 30 and 38 which extend through check valves 28 and 36, respectively, permit the pressures -in subchambers 14 and 16 to equalize when the pressure pulsations cease. Consequently, the device lis not sensitive to steady state pressures.

Although this invention has been described in connection with a specific embodiment, it will be obvious to those skilled in the art that various changes may be made in the form, structure, and arrangement of parts without departing from the :spirit Iof the invention. For example, a piston or bellows could be used in place of the diaphragm. Similarly, ball check or flapper type valves could be used in place of the valves shown on the drawing. Furthermore, tlhe device can operate with Vonly one check valve but will utilize less of the available force. Accord-` ingly,'we do not desire to be limited -to the specific embodiment disclosed herein primarily for purposes -of illustration, but instead desire protection falling within the scope of the appended claims.

Having thus described the various -features of the invention wha-t we claim as new and desire'to secure by Letters Patent is:

1. A device for detecting pulsating pressures comprising a housing having a chamber therein, a movable diaphragm located in said chamber and dividing said chamber into first and second subchambers, a control rod operatively connected to said diaphragm and movable therewith, rst passage means for connecting said first subchamber with a pneumatic pressure source, second passage means for connecting the second A subchamber with the same pneumatic pressure source, a rst spring loaded check valve located in said irst passage means, said tirst check valve being arranged to open and permit increased communication between the pressure source and said rst subchamber during the high pressure portion of a pulsating pressure cycle, a second spring loaded check valve located in said second passage means, said second check valve being arranged to open and permit increased communication between the pressure source and said second subchamber during the low pressure portion of a pulsating pressure cycle, and restricted passages located in each sures in the first and second subchambers during steady of said check valves for permitting equalization of presstate pressure applications when pulsing pressures are not emanating from the pressure source.

2. A device for detecting pulsating pressures comprising a housing having a chamber therein, movable pressure responsive means disposed in said chamber, means operatively connected to said pressure responsive means and movable therewith, first passage means for connecting one side of Said pressure responsive means with a pneumatic pressure source, second passage means for connecting the other side of said pressure responsive means with the same pressure source, first valve means located in said first passage means, s aid first valve means being arranged to open and permit increased communication between the pressure source and said one side of said pressure responsivemeans during the high pressure portion of a pulsating pressure cycle, second valve means located in said second passage means, said second valve means being arranged to open and permit increased communcation between the pressure source and said other side of said pressure responsive means during the low pressure portion of a pulsating pressure cycle, and restrictive orifice means located in each of said passage means for permitting equalization of pressures on each side of said pressure responsive means during steady state pressure applications when pulsing pressures are not emanating from the pressure source.

3. A device for detecting pulsating pressures comprising a housing having a chamber therein, movable pressure responsive means disposed in said chamber, means operatively connected to said pressure responsive means and movable therewith, passage means for connecting each side of said pressure responsive means with a pneumatic pressure source, first and second valve means located in said passage means, said first and second valve means being arranged to alternately open and permit unrestricted communication between the pressure source and each side of the pressure responsive means during high and low pressure portions of a pulsating pressure cycle, and restrictive orifices located in said first and second valve means for permitting equalization of pressures on each side of said pressure responsive means during steady state pressure applications.

4. A device for detecting pulsating pressures comprising a housing having a chamber therein, pressure responsive means located in Said chamber and dividing `said chamber into first and second subchambers, control means operatively connected to said pressure responsive means and movable therewith, passage means for connecting each of said subchambers with a pneumatic pressure source, valve means located in said passage means, said valve means being arranged to open and permit increased communication between the pressure source and one of said subchambers during the high pressure portion of a pulsating pressure cycle, and restrictive orifice means located in said passage means for permitting equalization of pressures in each subchamber during steady state pres sure applications.

References Cited by the Examiner UNITED STATES PATENTS 1,924,091 8/ 1933 Eisenhour 181-0.5

LOUIS R. PRINCE, Primary Examiner.

DAVID SCHONBERG, Examiner.

r D. O. WOODIEL, Assistant Examiner. 

1. A DEVICE FOR DETECTING PULSATING PRESSURES COMPRISING A HOUSING HAVING A CHAMBER THEREIN, A MOVABLE DIAPHRAGM LOCATED IN SAID CHAMBER AND DIVIDING SAID CHAMBER INTO FIRST AND SECOND SUBCHAMBERS, A CONTROL ROD OPERATIVELY CONNECTED TO SAID DIAPHRAGM AND MOVABLE THEREWITH, FIRST PASSAGE MEANS FOR CONNECTING SAID FIRST SUBCHAMBER WITH A PNEUMATIC PRESSURE SOURCE, SECOND PASSAGE MEANS FOR CONNECTING THE SECOND SUBCHAMBER WITH THE SAME PNEUMATIC PRESSURE SOURCE, A FIRST SPRING LOADED CHECK VALVE LOCATED IN SAID FIRST PASSAGE MEANS, SAID FIRST CHECK VALVE BEING ARRANGED TO OPEN AND PERMIT INCREASED COMMUNICATION BETWEEN THE PRESSURE SOURCE AND SAID FIRST SUBCHAMBER DURING THE HIGH PRESSURE PORTION OF A PULSATING PRESSURE CYCLE, A SECOND SPRING LOADED CHECK VALVE LOCATED IN SAID SECOND PASSAGE MEANS, SAID SECOND CHECK VALVE BEING ARRANGED TO OPEN AND PERMIT INCREASED COMMUNICATION BETWEEN THE PRESSURE SOURCE AND SAID SECOND SUBCHAMBER DURING THE LOW PRESSURE SOURCE AND SAID SECOND ING PRESSURE CYCLE, AND RESTRICTED PASSAGES LOCATED IN EACH SURES IN THE FIRST AND SECOND SUBCHAMBERS DURING STEADY OF SAID CHECK VALVES FOR PERMITTING EQUALIZATION OF PRESSTATE PRESSURE APPLICATIONS WHEN PULSING PRESSURES ARE NOT EMANATING FROM THE PRESSURE SOURCE. 